/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.druid.msq.logical.stages;

import org.apache.druid.msq.logical.LogicalInputSpec;
import org.apache.druid.sql.calcite.planner.PlannerContext;
import org.apache.druid.sql.calcite.planner.querygen.DruidQueryGenerator.DruidNodeStack;
import org.apache.druid.sql.calcite.planner.querygen.SourceDescProducer.SourceDesc;
import org.apache.druid.sql.calcite.rule.logical.DruidUnnest;

import java.util.Collections;

public class UnnestStage
{
  public static LogicalStage buildUnnestStage(LogicalStage inputStage, DruidNodeStack stack)
  {
    DruidUnnest unnest = (DruidUnnest) stack.getNode();
    PlannerContext plannerContext = stack.getPlannerContext();
    LogicalInputSpec logicalInputSpec = LogicalInputSpec.of(inputStage);
    SourceDesc sourceDesc = logicalInputSpec.getSourceDesc();
    SourceDesc unnestSD = unnest.getSourceDesc(plannerContext, Collections.singletonList(sourceDesc));
    return new SegmentMapStage(unnestSD, Collections.singletonList(logicalInputSpec));
  }
}
